5,796 research outputs found
Channel Model in Urban Environment for Unmanned Aerial Vehicle Communications
In order to develop and analyze reliable communications links for unmanned
aerial vehicles (UAVs), accurate models for the propagation channel are
required. The radio channel properties in the urban scenario are different from
those in the suburb scenario and open area due to so many scattering paths from
office buildings, especially when the UAV flies in the low altitude. We took
some measurement campaigns on the campus of Tsinghua University with crowded
apartments and office buildings. Based on the measurement result we extract the
main parameters of pathloss model, and propose a simplified Saleh-Valenzuela
(SV) model with specific parameters. The typical scene of central lawn is
compared with the office buildings in the analysis of K-factor and
root-mean-square (RMS) delay spread.Comment: to prepare in European Conference on Antennas and Propagetion
(EUCAP), 201
A Survey of Air-to-Ground Propagation Channel Modeling for Unmanned Aerial Vehicles
In recent years, there has been a dramatic increase in the use of unmanned
aerial vehicles (UAVs), particularly for small UAVs, due to their affordable
prices, ease of availability, and ease of operability. Existing and future
applications of UAVs include remote surveillance and monitoring, relief
operations, package delivery, and communication backhaul infrastructure.
Additionally, UAVs are envisioned as an important component of 5G wireless
technology and beyond. The unique application scenarios for UAVs necessitate
accurate air-to-ground (AG) propagation channel models for designing and
evaluating UAV communication links for control/non-payload as well as payload
data transmissions. These AG propagation models have not been investigated in
detail when compared to terrestrial propagation models. In this paper, a
comprehensive survey is provided on available AG channel measurement campaigns,
large and small scale fading channel models, their limitations, and future
research directions for UAV communication scenarios
Underlay Drone Cell for Temporary Events: Impact of Drone Height and Aerial Channel Environments
Providing seamless connection to a large number of devices is one of the
biggest challenges for the Internet of Things (IoT) networks. Using a drone as
an aerial base station (ABS) to provide coverage to devices or users on ground
is envisaged as a promising solution for IoT networks. In this paper, we
consider a communication network with an underlay ABS to provide coverage for a
temporary event, such as a sporting event or a concert in a stadium. Using
stochastic geometry, we propose a general analytical framework to compute the
uplink and downlink coverage probabilities for both the aerial and the
terrestrial cellular system. Our framework is valid for any aerial channel
model for which the probabilistic functions of line-of-sight (LOS) and
non-line-of-sight (NLOS) links are specified. The accuracy of the analytical
results is verified by Monte Carlo simulations considering two commonly adopted
aerial channel models. Our results show the non-trivial impact of the different
aerial channel environments (i.e., suburban, urban, dense urban and high-rise
urban) on the uplink and downlink coverage probabilities and provide design
guidelines for best ABS deployment height.Comment: This work is accepted to appear in IEEE Internet of Things Journal
Special Issue on UAV over IoT. Copyright may be transferred without notice,
after which this version may no longer be accessible. arXiv admin note: text
overlap with arXiv:1801.0594
Multi-layer Unmanned Aerial Vehicle Networks: Modeling and Performance Analysis
Since various types of unmanned aerial vehicles (UAVs) with different
hardware capabilities are introduced, we establish a foundation for the
multi-layer aerial network (MAN). First, the MAN is modeled as K layer ANs, and
each layer has UAVs with different densities, floating altitudes, and
transmission power. To make the framework applicable for various scenarios in
MAN, we consider the transmitter- and the receiver-oriented node association
rules as well as the air-to-ground and air-to-air channel models, which form
line of sight links with a location-dependent probability. We then newly
analyze the association probability, the main link distance distribution,
successful transmission probability (STP), and area spectral efficiency (ASE)
of MAN. The upper bounds of the optimal densities that maximize STP and ASE are
also provided. Finally, in the numerical results, we show the optimal UAV
densities of an AN that maximize the ASE and the STP decrease with the altitude
of the network. We also show that when the total UAV density is fixed for two
layer AN, the use of single layer in higher(lower) altitude only for all UAVs
can achieve better performance for low(high) total density case, otherwise,
distributing UAVs in two layers, i.e., MAN, achieves better performance
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